Code Design Rationale Investigator
cursor/plugins
Digs into why code is shaped the way it is by checking git history, pull requests and connected tools in parallel, then reporting a cited read on the tradeoffs.
근본원인 분석(RCA) 방법론 상세 가이드. An agent skill from revfactory/harness-100.
Install Rca Methodology
$ npx skills add revfactory/harness-100 --skill rca-methodology -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install revfactory/harness-100 rca-methodology --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .claude/skills && cp -r skills-src/ko/25-incident-postmortem/.claude/skills/rca-methodology .claude/skills/rca-methodology && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "rca-methodology" agent skill from https://github.com/revfactory/harness-100/tree/main/ko/25-incident-postmortem/.claude/skills/rca-methodology into .claude/skills/rca-methodology/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "rca-methodology", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/revfactory/harness-100/tree/main/ko/25-incident-postmortem/.claude/skills/rca-methodologyType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add revfactory/harness-100 --skill rca-methodology -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install revfactory/harness-100 rca-methodology --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .agents/skills && cp -r skills-src/ko/25-incident-postmortem/.claude/skills/rca-methodology .agents/skills/rca-methodology && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "rca-methodology" agent skill from https://github.com/revfactory/harness-100/tree/main/ko/25-incident-postmortem/.claude/skills/rca-methodology into .agents/skills/rca-methodology/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "rca-methodology", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add revfactory/harness-100 --skill rca-methodology -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install revfactory/harness-100 rca-methodology --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/ko/25-incident-postmortem/.claude/skills/rca-methodology .cursor/skills/rca-methodology && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "rca-methodology" agent skill from https://github.com/revfactory/harness-100/tree/main/ko/25-incident-postmortem/.claude/skills/rca-methodology into .cursor/skills/rca-methodology/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "rca-methodology", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/revfactory/harness-100.git --path ko/25-incident-postmortem/.claude/skills/rca-methodology--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add revfactory/harness-100 --skill rca-methodology -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install revfactory/harness-100 rca-methodology --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/ko/25-incident-postmortem/.claude/skills/rca-methodology .gemini/skills/rca-methodology && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "rca-methodology" agent skill from https://github.com/revfactory/harness-100/tree/main/ko/25-incident-postmortem/.claude/skills/rca-methodology into .gemini/skills/rca-methodology/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "rca-methodology", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install revfactory/harness-100 rca-methodologyInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add revfactory/harness-100 --skill rca-methodology -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .github/skills && cp -r skills-src/ko/25-incident-postmortem/.claude/skills/rca-methodology .github/skills/rca-methodology && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "rca-methodology" agent skill from https://github.com/revfactory/harness-100/tree/main/ko/25-incident-postmortem/.claude/skills/rca-methodology into .github/skills/rca-methodology/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "rca-methodology", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add revfactory/harness-100 --skill rca-methodology -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install revfactory/harness-100 rca-methodology --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/revfactory/harness-100.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/ko/25-incident-postmortem/.claude/skills/rca-methodology .opencode/skills/rca-methodology && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "rca-methodology" agent skill from https://github.com/revfactory/harness-100/tree/main/ko/25-incident-postmortem/.claude/skills/rca-methodology into .opencode/skills/rca-methodology/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "rca-methodology", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
rca-methodology- GitHub stars
- 1.3k
- Token cost
- ~899 tokens
- SKILL.md length
- 234 words
- Files
- 1
- Skills in repo
- 464
- Repo updated
- First seen
- Licence
- Apache-2.0
At a glance
근본원인 분석(RCA) 방법론 상세 가이드. An agent skill from revfactory/harness-100.
- Works in 4 steps: 5 Whys 기법 → 피시본 다이어그램 (Ishikawa) → Fault Tree Analysis (FTA) → …
- Tasks that involve Root cause analysis
- SKILL.md covers 1. 5 Whys 기법, 2. 피시본 다이어그램 (Ishikawa), 3. Fault Tree Analysis (FTA) and 4. 변경점 분석 (Change Analysis), plus 2 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Rca Methodology is an agent skill from revfactory/harness-100. 근본원인 분석(RCA) 방법론 상세 가이드. 5 Whys, 피시본 다이어그램, Fault Tree Analysis, 변경점 분석 등 구조화된 RCA 기법과 인지 편향 방지 체크리스트. '근본원인 분석', 'RCA', '5 Whys', '피시본', 'Fault Tree', '원인 분석 방법론', '변경점 분석' 등 장애 원인 분석 시 이 스킬을 사용한다. root-cause-investigator의 분석 역량을 강화한다. 단, 타임라인 재구성이나 재발방지 대책 수립은 이 스킬의 범위가 아니다.
Its SKILL.md is about 900 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Development, covering Root cause analysis. The licence is Apache-2.0.
When your agent uses it
- Tasks that involve Root cause analysis
Example prompts
- “5 Whys”
- “Fault Tree”
- “/rca-methodology”
Workflow steps
4 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit 8e8d35c. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are markdown).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Rca Methodology loads about 899 tokens when it runs. Until then it costs about 73 tokens; SKILL.md has 234 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from revfactory/harness-100 at commit 8e8d35c, republished under its Apache-2.0 licence (© revfactory). 234 words, ~899 tokens.
Download SKILL.mdSave it as
.claude/skills/rca-methodology/SKILL.md (or your agent's skills folder).- name
- rca-methodology
- description
- 근본원인 분석(RCA) 방법론 상세 가이드. 5 Whys, 피시본 다이어그램, Fault Tree Analysis, 변경점 분석 등 구조화된 RCA 기법과 인지 편향 방지 체크리스트. '근본원인 분석', 'RCA', '5 Whys', '피시본', 'Fault Tree', '원인 분석 방법론', '변경점 분석' 등 장애 원인 분석 시 이 스킬을 사용한다. root-cause-investigator의 분석 역량을 강화한다. 단, 타임라인 재구성이나 재발방지 대책 수립은 이 스킬의 범위가 아니다.
RCA Methodology — 근본원인 분석 방법론 가이드
장애의 근본원인을 체계적으로 추적하는 구조화된 분석 기법 모음.
1. 5 Whys 기법
수행 절차
문제: 결제 서비스가 30분간 다운되었다.
Why 1: 왜 결제 서비스가 다운되었나?
→ DB 커넥션 풀이 소진되었다.
Why 2: 왜 커넥션 풀이 소진되었나?
→ 느린 쿼리가 커넥션을 장시간 점유했다.
Why 3: 왜 느린 쿼리가 발생했나?
→ 인덱스 없이 전체 테이블 스캔을 수행했다.
Why 4: 왜 인덱스가 없었나?
→ 신규 기능 배포 시 마이그레이션에 인덱스 추가를 누락했다.
Why 5: 왜 인덱스 누락을 감지하지 못했나?
→ 쿼리 성능 검증이 배포 파이프라인에 포함되지 않았다.
근본원인: 배포 파이프라인에 쿼리 성능 검증 단계 부재5 Whys 주의사항
| 함정 | 설명 | 방지법 |
|---|---|---|
| 너무 일찍 멈춤 | 2~3단계에서 원인 확정 | "이것을 고치면 재발 방지되나?" 검증 |
| 비난으로 귀결 | "누가 실수했나"로 끝남 | 시스템/프로세스 원인에 집중 |
| 단일 경로만 추적 | 복합 원인 놓침 | 각 단계에서 분기 검토 |
| 추측 기반 답변 | 증거 없는 가설 | 로그/메트릭으로 검증 |
2. 피시본 다이어그램 (Ishikawa)
┌─ 사람 ──────── 배포 담당자 교육 부족
│ 코드 리뷰 생략
│
├─ 프로세스 ──── 배포 체크리스트 미준수
│ 성능 테스트 미실시
│
결제 서비스 다운 ←──┼─ 기술 ──────── 인덱스 누락
│ 커넥션 풀 사이즈 부족
│
├─ 환경 ──────── 프로덕션 데이터 규모 미반영
│ 스테이징 환경 불일치
│
└─ 모니터링 ──── 느린 쿼리 알림 미설정
DB 메트릭 대시보드 부재6M 카테고리 (소프트웨어 적용)
| 전통 6M | 소프트웨어 적용 | 조사 항목 |
|---|---|---|
| Man | 사람/팀 | 교육, 커뮤니케이션, 온콜 체계 |
| Method | 프로세스 | 배포 절차, 변경 관리, 승인 흐름 |
| Machine | 기술/인프라 | 서버, DB, 네트워크, 코드 |
| Material | 데이터/입력 | 입력 데이터, 외부 API 응답 |
| Measurement | 모니터링 | 알림, 메트릭, 로그, 트레이싱 |
| Environment | 환경 | 설정, 환경변수, 의존 서비스 |
3. Fault Tree Analysis (FTA)
결제 서비스 장애 (Top Event)
│
┌─────┤ OR ├─────┐
│ │
DB 장애 애플리케이션 장애
│ │
┌─────┤ OR ├─────┐ ┌───┤ AND ├───┐
│ │ │ │
커넥션 풀 소진 디스크 풀 느린 쿼리 높은 트래픽
│ │
┌─────┤ AND ├─────┐ ┌─────┤ OR ├─────┐
│ │ │ │
인덱스 누락 대량 데이터 신규 코드 배포 스키마 변경확률 계산:
OR 게이트: P(A OR B) = 1 - (1-P(A)) × (1-P(B))
AND 게이트: P(A AND B) = P(A) × P(B)
예: P(느린쿼리)=0.3, P(높은트래픽)=0.2
P(앱장애) = 0.3 × 0.2 = 0.06 (6%)4. 변경점 분석 (Change Analysis)
장애 발생 전후 변경 사항 조사:
| 변경 시점 | 변경 내용 | 변경자 | 영향 범위 | 장애 상관 |
|----------|----------|--------|----------|----------|
| T-2h | 결제 API v2.3 배포 | 김개발 | 결제 서비스 | ✅ 높음 |
| T-1h | Redis 설정 변경 | 박운영 | 캐시 서비스 | ❓ 중간 |
| T-30m | CDN 캐시 퍼지 | 이마케팅 | 프론트엔드 | ❌ 낮음 |
상관 관계 판단 기준:
1. 시간적 근접성: 변경 시점 ↔ 장애 발생 시점
2. 범위 일치: 변경 범위 ↔ 장애 영향 범위
3. 롤백 효과: 변경 롤백 시 장애 해소 여부인지 편향 방지 체크리스트
| 편향 | 설명 | 방지법 |
|---|---|---|
| 확증 편향 | 첫 가설에 맞는 증거만 수집 | 반례를 적극적으로 찾기 |
| 사후 확신 편향 | "당연히 이게 원인이지" | 당시 시점의 정보만으로 판단 |
| 가용성 편향 | 최근 경험한 유사 장애와 동일시 | 증거 기반 분석 강제 |
| 기본 귀인 오류 | 사람 탓으로 귀결 | 시스템/프로세스 원인 우선 |
| 앵커링 | 첫 보고 내용에 고착 | 다수 관점에서 독립적 분석 |
RCA 기법 선택 가이드
| 상황 | 추천 기법 | 이유 |
|---|---|---|
| 단순 장애, 빠른 분석 필요 | 5 Whys | 경량, 즉시 수행 가능 |
| 복합 원인 의심 | 피시본 | 다차원 원인 탐색 |
| 안전 관련 심각 장애 | FTA | 정량적, 체계적 |
| 배포 직후 장애 | 변경점 분석 | 원인 후보 좁히기 |
| 모든 경우 | 5 Whys + 변경점 분석 병행 | 빠르면서도 체계적 |
© revfactory, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in ko/25-incident-postmortem/.claude/skills/rca-methodology of revfactory/harness-100.
Open the folder on GitHubat commit 8e8d35c
Compare with similar skills
Rca Methodology next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Rca Methodology this skillrevfactory/harness-100 | 1.3k | — | ~899 | Automated safety check: Pass | Apache-2.0 | |
| Code Design Rationale Investigatorcursor/plugins | 10k | 9 repos | ~2.6k | Automated safety check: Pass | None | |
| OpenLogi macOS Permissions TriageAprilNEA/OpenLogi | 23k | — | ~2.5k | Automated safety check: Notes | Apache-2.0 | |
| Bug Finder for daisyUIsaadeghi/daisyui | 43k | — | ~2.3k | Automated safety check: Pass | MIT | |
| Root Cause Debugginggarrytan/gstack | 136k | — | ~1.4k | Automated safety check: Pass | MIT | |
| Graph-Based Bug Tracingtirth8205/code-review-graph | 32k | 1 repos | ~287 | Automated safety check: Pass | MIT |
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Questions about Rca Methodology
What does Rca Methodology do?
근본원인 분석(RCA) 방법론 상세 가이드. An agent skill from revfactory/harness-100. Rca Methodology is an agent skill from revfactory/harness-100. 근본원인 분석(RCA) 방법론 상세 가이드.
When should I use Rca Methodology?
Rca Methodology fits situations like: tasks that involve Root cause analysis.
How do I install Rca Methodology in Claude Code?
Run `npx skills add revfactory/harness-100 --skill rca-methodology -a claude-code`. Or copy the skill folder (ko/25-incident-postmortem/.claude/skills/rca-methodology in revfactory/harness-100) into .claude/skills/rca-methodology in your project. Claude Code loads it when a task matches its description.
How do I install Rca Methodology in Codex?
Run `npx skills add revfactory/harness-100 --skill rca-methodology -a codex`. Or copy the skill folder (ko/25-incident-postmortem/.claude/skills/rca-methodology in revfactory/harness-100) into .agents/skills/rca-methodology in your project. Codex loads it when a task matches its description.
Can I use Rca Methodology in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add revfactory/harness-100 --skill rca-methodology -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/rca-methodology, .gemini/skills/rca-methodology, .github/skills/rca-methodology and .opencode/skills/rca-methodology in your project.
What does Rca Methodology need to run?
SKILL.md names no scripts, command-line tools or credentials: Rca Methodology is instructions for the agent only.
Does Rca Methodology access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Rca Methodology safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Rca Methodology use?
Rca Methodology is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Rca Methodology use?
About 899 tokens (SKILL.md is roughly 3.6k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Rca Methodology?
Skills that share tags, products or a category with Rca Methodology: Code Design Rationale Investigator (cursor/plugins, 10k stars), OpenLogi macOS Permissions Triage (AprilNEA/OpenLogi, 23k stars), Bug Finder for daisyUI (saadeghi/daisyui, 43k stars) and Root Cause Debugging (garrytan/gstack, 136k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Rca Methodology?
revfactory (a GitHub user) maintains it in revfactory/harness-100, which has 1,290 GitHub stars. The repository holds 464 skills in this directory. The repository was last updated on March 22, 2026.
Source: revfactory/harness-100 on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.